The present invention relates to a rotary die cutter for converting sheets of paperboard or other web materials and, more particularly, to a rotary die cutter having an anvil cylinder and a pair of alternately operable die cylinders mounted for vertical support and rectilinear translation.
Rotary die cutters are well known in the art and, in one common application, are used to cut, slot, or notch paperboard sheets to provide blanks for cartons. In one common application, corrugated paperboard blanks, which may have been previously printed, are processed through a rotary die cutter to provide slots which define the flaps for cartons made from the paperboard blanks, for example, in a downstream folder-gluer.
The increasing capability of this machinery for accuracy and high speed production has resulted in a similar need for high speed die cylinder change at order change without sacrificing accuracy. It has also been found that, with the typical structural connection between the die cutter and the upstream print rolls, vibration and shock loads developed at the die cutter were transmitted to the printing equipment. In particular, low frequency, high amplitude shock loads, such as may be generated by loosened plywood backing for the cutting die on the die cylinder, result in the transmission of extremely high and potentially damaging shock loads to the print stations.